Microstructure Development on Sintered Ti/HA Biocomposites Produced by Powder Metallurgy

Titanium-based composites with in-situ calcium and phosphor phases were prepared by powder metallurgy processing with titanium and hydroxyapatite (HA) powders. The mixtures were performed in a friction mill with alcohol for 5 hours, dried in a rotating evaporator, pressed at 600 MPa and sintered at 1200 degrees C for 2 hours in argon atmosphere. Crystal phases of the as-fabricated composite are found to be, alpha-Ti, CaTiO3, Ca-3(PO4)(2) and TixPy phase(s). The analyses revealed that titanium particles were covered with a compact layer of TixPy and CaTiO3 phases, which resulted from the decomposition of HA into CaTiO3 and beta-Ca-3(PO4)(2) at approximately 1025 degrees C. Then the reactions were followed by the decomposition of beta-Ca-3(PO4)(2), resulting in the growth of CaTiO3 layer and in the nucleation and growth of TixPy phase(s).